Acoustic Emission Structure-Borne Noise Measurements on Aircraft during Flight.

The assurance of structural integrity is a major requirement of service-life maintenance procedures for large commercial and military aircraft. This generates requirements for reliable and cost effective techniques for detecting small fatigue cracks and for following their growth. Research conducted at Lockheed-Georgia and elsewhere demonstrates that the acoustic emission from a fatigue crack can be detected in a noisy environment. This paper summarizes the results of acoustic emission work performed on-board an aircraft. The characteristics of the acoustic emission signal as the crack progresses from crack initiation and the on-board system requirements will be presented.